Biocides, and in particular pesticides such as fungicides, insecticides and herbicides, are important auxiliary agents for agriculture in order to protect crops and to increase their yields. Depending on the various and often very specific needs a magnitude of actives exist which show very different chemical structures and behaviours. Nevertheless, it is well known from the state of the art that it remains difficult to prepare concentrates of these actives which are exhibiting a satisfying stability, especially if stored at very low or elevated temperatures over a longer period. As a matter of fact, the solutions show a strong tendency to either separate or to form crystals, which makes it necessary to re-disperse the actives in the compositions prior to every application in order to obtain a homogenous product. In addition, many biocides, especially pesticides, do exhibit suboptimal biological efficacy because of insufficient retention, adhesion, wetting, or penetration. Therefore, there is a need for a corresponding adjuvant which allows access to a better biological performance.
Wirth, Storp and Jacobsen have established a correlation between dynamic surface tension (DST) and leaf retention of agricultural spray solutions [Pestic. Sci. 33, p 411-420 (1991)]. In Surfaplus' Adjuvant Newsletter (ed. Hans de Ruiter), Vol. 5, p 4-5 (2008) a relationship between structure and performance with regard to DST is discussed:
“[ . . . ] a short and/or branched hydrophobe, a high EO content and endcapping an EO chain with PO.”
Additionally, a low CMC shows little intermolecular forces or high flexibility to migrate to new surfaces. Explicitly the alkoxylated alcohol C9/C11(EO)5.5(PO)3.5 is mentioned. Under the trademark Tego Wet 5xx alkoxylation products of highly branched alcohols such as e.g. 3,5,5-trimethylhexanol are sold exhibiting an excellent low of dynamic surface tension and small foam potential. However, all the products found in the market use a synthetic starting alcohol as raw material, while the trend in agro science leads to products based on renewable, fully degradable sources.
Therefore, the problem underlying the present invention has been to develop new additives for agrochemical compositions, useful as solvents, adjuvants, emulsifiers and the like, which are based on renewable alcohols. In particular, the new additives should exhibit a low foaming behavior and both a low dynamic and a low static surface tension. A low dynamic surface tension is attributed to an increased retention of agricultural sprays on crops, notably monocots or grasses which typically have a lower leaf area. A low static surface tension allows quicker and hence better penetration of the agricultural spray, so uptake of an active ingredient is enhanced leading to better biological performance.